Chemistry

Chemical Reactions and Equations

684 Questions

Chemical reactions and equations form a foundational chemistry topic where students identify reaction products, balance chemical formulas, and classify reaction types. It covers critical mechanisms like Markovnikov's rule, precipitation, and endothermic or exothermic processes. These questions are highly common in general science sections of state and central government competitive exams.

Endothermic reactionsPrecipitation reactionsDehydrohalogenation of alkyl halidesChemical equation balancingReaction product identification

Chemical Reactions and Equations Questions

Multiple choice

The Hofmann and Hinsberg's reagent is used in _____________.

  1. Separation of amine

  2. Producing alkyl isocynanide

  3. Formation of Schiff's base

  4. Option 2 and 3 correct

  5. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This option is correct because the Hofmann and Hinsberg's reagent is used in the separation of amine from the mixture of primary, secondary and tertiary amine.

Multiple choice

Which of the following statements is true about the Finkelstein reaction?

  1. Alkyl iodide is prepared with alkyl chloride in presence of KI solution.

  2. Alkane are prepared by alkyl halides of two molecules with metal sodium.

  3. The iodine forms the ester with silver salts.

  4. Alkyl halides are formed by the decomposition of silver salts of fatty acid with chlorine.

  5. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This option is correct because the Alkyl iodide is prepared by the treatment of primary alkyl halides with alkali metal halides leads to the replacement of halogen to formed the alkyl iodide.

Multiple choice

Which of the following statements is/are true? A. Frankland reaction: The formation of alkenes by the action of zinc on alkyl halides. B. Reforming involves conversion of aliphatic into aromatic hydrocarbons. C. Corey-House reaction can be used to prepare only alkenes with odd number of carbon atoms.

  1. Only A

  2. Only B

  3. Only C

  4. Only A and C

  5. Only A and B
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This option is correct because the formation of alkenes by the action of zinc on alkyl halides is known as Frankland reaction and reforming involves conversion of aliphatic into aromatic hydrocarbons.

Multiple choice

Assertion: Benzaldehyde forms two oximes on reacting with NH2OH. Reason: The two oximes arise due to geometrical isomerism around C = N bond.

  1. Both A and R are true and R is the correct explanation of A.

  2. Both A and R are true but R is NOT the correct explanation of A.

  3. A is false, but R is true.

  4. A is true, but R is false.

  5. Both A and R are false.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This option is correct because benzaldehyde forms two oximes on reacting with NH2OH and the two oximes arise due to geometrical isomerism around C = N bond.

Multiple choice

Which of the reactions can not be used to distinguish allyl bromide from n-propyl bromide?

  1. Shaking with an aqueous solution of AgNO3.

  2. Boiling with aqueous KOH solution followed by acidification with dil. HNO3 and addition of AgNO3 solution.

  3. Fusion with sodium metal followed by acidification with dil. HNO3 and addition of AgNO3 solution.

  4. Both options 2 and 3

  5. All are correct
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

On boiling with aqueous KOH solution, both allyl bromide and n-propyl bromide undergo hydrolysis, and hence give pale yellow precipitate of AgBr and fusion will convert both into NaBr and would subsequently give pale yellow precipitate of AgBr. Hence, option 2 and 3 both are correct.

Multiple choice

Under the certain conditions an alkyl halide reacts with base to give an alkene and HCl (elimination reaction) for example: R-CH2-CH2-Cl → R-CH2=CH2 + HCl The extent of these reactions depends on the structure of alkyl halides (e.g. primary, secondary or tertiary). The relative extent to which such reactions take place is in the order (of haloalkanes) _______________.

  1. Primary > secondary > tertiary

  2. Primary > secondary > tertiary

  3. Primary > secondary < tertiary

  4. Primary < secondary > tertiary<secondary></secondary>

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This option is correct because on the basis of the stability of carbocation, which is formed during the reaction, i.e., 1˚ < 2˚ < 3˚ alkyl halide.

Multiple choice

The formula of hydride of halogen (X) in period 3 will be

  1. HX

  2. H2X

  3. HX2

  4. H2X3
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The halogen in period 3 will be having 7 electrons in the outermost third shell. This must require one electron for its octet to be completed. So, each of its atoms needs to make bond with one hydrogen atom which donates its one electron and hence, the formula HX.